Abstract:The influences of simulated acid rain and aluminum (Al) addition on main chemical quality and aluminum accumulation in tea leaves were investigated, which grown in acid deposition regions of red soil in southern China. The tea plants were treated with three pH levels (3.0, 4.0, 5.0) of acid rain and four levels of Al addition (0, 10, 20, 30 mg L-1), respectively. The results showed that the contents of tea polyphenols and caffeine was the highest in tea leaves treated with pH 4.0 acid rain, and the contents of amino acid, catechin and soluble sugar decreased with increasing acidity, while the flavonoid content showed no significant difference among three levels of pH solutions (P<0.05). With the increasing Al concentrations in solution, the contents of tea polyphenols, caffeine, amino acid, catechin, flavonoid and soluble sugar in tea leaves increased first and decreased later. Simulated acid rain and Al addition had significant interactive effects on polyphenols, catechin and flavones, while no interactions on caffeine, soluble sugar and amino acid were found. The catechin content in tea leaves was inhibited by the highest pH (5.0) and Al concentration (30 mg L-1) in solution. The Al accumulation in tea leaves was the highest in the treatment of middle Al concentration in solution (20 mg L-1), while the Al accumulation in roots, shoots and old leaves were not significantly different among three treatments of Al concentration. The Al accumulation in tea leaves increased with decreasing pH solution under lower Al concentration (10 mg L-1), while the Al content in tea leaves was the lowest under the lowest pH (3.0) and the highest Al concentration (30 mg L-1) in solution among the twelve treatments. Therefore, it was recommend that the moderate acidity (pH close to 4.0) and Al content (10~20 mg L-1) in solution was advantaged to improve tea quality.
